1. Field of the Invention
The invention relates to a hollow golf club head, and more particularly to a golf club head having a wood-type shape or a similar shape thereto.
2. Description of the Related Art
As wood-type golf club heads such as drivers and fairway woods, hollow metallic heads are widely in use. Generally, the hollow wood-type golf club head has a face portion for hitting a ball; a crown portion constituting an upper surface portion of the golf club head; a sole portion constituting a bottom surface portion of the golf club head; a side portion constituting side surface portions on the toe side, the rear side, and the heel side of the golf club head; and a hosel portion. A shaft is inserted into the hosel portion, and is fixed by a bonding adhesive or the like. Recently, golf clubs called utility clubs are also commercially available in large numbers, and various golf clubs having a head similar to the aforementioned wood-type golf club head (i.e., having the face portion, the sole portion, the side portion, the crown portion, and the hosel portion) are also commercially available.
Aluminum alloy, stainless steel, and a titanium alloy are used as metal forming this hollow golf club head. In particular, titanium alloy has come to be used widely in recent years.
It becomes possible to enlarge the sweet spot, by increasing the volume of the hollow golf club head. To prevent an increase in the weight of the golf club head in consequence of the increase in the volume thereof, it has been conceived to adopt a fiber reinforced resin whose specific gravity is far smaller than metals. In this case, since the face surface for hitting the ball needs to be made of metal to ensure the strength, portions other than the face portion are consequently made of the fiber reinforced resin.
For example, US 2004/0005936 A1 discloses a golf club head adopting the carbon fiber reinforced thermosetting resin (CFRP).